ixgbe: Priority tag FIP frames

Currently FIP (FCoE Initialization Protocol) frames
are going untagged. This causes various problems
with FCFs (switches) that have negotiated a priority
over dcbx. This patch tags FIP frames with the same
priority as the FCoE frames.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>